Apparatuses with various configurations are conventionally known as a kneading apparatus performing a kneading treatment for a kneaded material. A kneading unit in such a kneading apparatus is made up of components such as a screw element primary intended for transportation of the kneaded material and a kneading block primary intended for kneading. These components are referred to as segment parts, and a plurality of segment parts is selectively combined and mounted on a shaft (e.g., a spline shaft) so as to configure the kneading unit having required specifications/functions (see, e.g., Patent Document 1).
To selectively combine and mount a plurality of segment parts on the shaft in this way, these segment parts are prepared as parts having a plurality of predefined lengths. For example, three types of parts having the lengths of 30 mm, 45 mm, and 60 mm are prepared as screw segment parts having the outer diameter of 50 mm and, three types of parts having the lengths of 50 mm, 80 mm, and 100 mm are prepared as screw segment parts having the outer diameter of 90 mm.